The present invention relates to voltage regulators.
Voltage regulators, such as DC-to-DC converters, are used to provide stable voltage sources for electronic systems. Efficient DC-to-DC converters are particularly needed for battery management in low power devices, such as laptop computers and mobile phones. Switching voltage regulators (or simply "switching regulators") are known to be an efficient type of DC-to-DC converter. A switching regulator generates an output voltage by converting an input DC voltage into a high frequency voltage, and filtering the high frequency voltage to generate the output DC voltage.
Conventional switching regulators include two switches. One switch is used to alternately couple and decouple an unregulated input DC voltage source, such as a battery, to a load, such as an integrated circuit. The other switch is used to alternately couple and decouple the load to ground. An output filter, typically including an inductor and an output capacitor, is coupled between the input voltage source and the load to filter the output of the switches and produce the output DC voltage. In low power application, there is typically also a discontinuous mode of operation where both switches are open, so that the output filter is not actively driven. In this case, the input and output terminals of the filter will resonate at a high frequency until equilibrium is reached. The high frequency component in the inductor current and the filter input voltage can conduct and radiate to nearby noise sensitive circuits, causing degradation in the performance of those circuits.